Blender Game Engine Car Crash
" I basically just want to be able to run my car into another object and have it randomly deform." that is very easy to do . add collision  sensor(senses collisions) to your car and add edit object replace mesh actuator (deforms your car(you have to make independent deformed model of your car))
here is example on how to make random deformations
https://www.youtube.com/watch?v=l32qN6CwzXs